Brake system and control method thereof

Abstract

A brake system may include: an electro mechanical brake provided with a motor and configured to brake a wheel of a vehicle based on a driving control of the motor; and a first controller configured to control the electro mechanical brake to provide current for reverse driving torque to the motor, based on a torque value of the motor at a time at which the motor starts being driven in a brake release direction according to a signal for operating an anti-lock brake system of the vehicle.

What is claimed is: 
     
         1 . A brake system comprising:
 an electro mechanical brake provided with a motor and configured to brake a wheel of a vehicle based on a driving control of the motor; and   a first controller configured to control the electro mechanical brake to provide current for reverse driving torque to the motor, based on a torque value of the motor at a time at which the motor starts being driven in a brake release direction according to a signal for operating an anti-lock brake system of the vehicle.   
     
     
         2 . The brake system of  claim 1 , further comprising a memory storing a plurality of preset reference torque values at the time at which the motor starts being driven in the brake release direction and current values for target reverse driving torque respectively corresponding to the plurality of preset reference torque values,
 wherein the first controller is configured to identify a reference torque value corresponding to the torque value of the motor at the time at which the motor starts being driven in the brake release direction from among the plurality of preset reference torque values, and determine a current value for target reverse driving torque corresponding to the identified reference torque value as a current value of the current for reverse driving torque.   
     
     
         3 . The brake system of  claim 1 , wherein the first controller is configured to stop providing the current for reverse driving torque to the motor, according to a speed of the motor reaching a preset target speed while the current for reverse driving torque is provided to the motor. 
     
     
         4 . The brake system of  claim 1 , further comprising a second controller configured to generate a signal for operating the anti-lock brake system based on occurrence of wheel slip of the vehicle. 
     
     
         5 . The brake system of  claim 4 , wherein the second controller is configured to identify occurrence of wheel slip of the vehicle based on an output signal from a wheel speed sensor of the vehicle, while a force is applied to a brake pedal of the vehicle. 
     
     
         6 . The brake system of  claim 5 , wherein the second controller is configured to identify that a force is applied to the brake pedal, according to reception of an output signal from a pedal sensor configured to detect a displacement of the brake pedal. 
     
     
         7 . The brake system of  claim 6 , wherein the second controller is configured to control the first controller to provide current for driving torque to the motor by providing the first controller with a pressure force of the electro mechanical brake according to an output signal from the pedal sensor, while no wheel slip of the vehicle occurs. 
     
     
         8 . A brake system comprising:
 an electro mechanical brake provided with a motor and configured to brake a wheel of a vehicle based on a driving control of the motor; and   a first controller configured to control the electro mechanical brake to provide current for reverse driving torque to the motor, until a speed of the motor reaches a preset target speed from a time at which the motor starts being driven in a brake release direction, based on conversion of an operation mode of the vehicle into an anti-lock brake system operation mode.   
     
     
         9 . The brake system of  claim 8 , further comprising a memory storing a plurality of preset reference torque values at the time at which the motor starts being driven in the brake release direction and current values for target reverse driving torque respectively corresponding to the plurality of preset reference torque values,
 wherein the first controller is configured to identify a reference torque value corresponding to a torque value of the motor at the time at which the motor starts being driven in the brake release direction from among the plurality of preset reference torque values, and determine a current value for target reverse driving torque corresponding to the identified reference torque value as a current value of the current for reverse driving torque.   
     
     
         10 . The brake system of  claim 8 , further comprising a second controller configured to convert the operation mode of the vehicle into the anti-lock brake system operation mode based on occurrence of wheel slip of the vehicle. 
     
     
         11 . The brake system of  claim 10 , wherein the second controller is configured to identify occurrence of wheel slip of the vehicle, based on an output signal from a wheel speed sensor of the vehicle, while a force is applied to a brake pedal of the vehicle. 
     
     
         12 . The brake system of  claim 11 , wherein the second controller is configured to identify that a force is applied to the brake pedal, according to reception of an output signal from a pedal sensor configured to detect a displacement of the brake pedal. 
     
     
         13 . The brake system of  claim 12 , wherein the second controller is configured to control the first controller to provide current for driving torque to the motor by providing the first controller with a pressure force of the electro mechanical brake according to the output signal from the pedal sensor, while no wheel slip of the vehicle occurs. 
     
     
         14 . A method for controlling a brake system, comprising:
 detecting a signal for operating an anti-lock brake system of a vehicle; and   controlling an electro mechanical brake to provide current for reverse driving torque to a motor, based on a torque value of the motor at a time at which the motor starts being driven in a brake release direction, according to the signal for operating the anti-lock brake system.   
     
     
         15 . The method of  claim 14 , further comprising:
 storing a plurality of preset reference torque values at the time at which the motor starts being driven in the brake release direction and current values for target reverse driving torque respectively corresponding to the plurality of preset reference torque values;   identifying a reference torque value corresponding to the torque value of the motor at the time at which the motor starts being driven in the brake release direction from among the plurality of preset reference torque values; and   determining a current value for target reverse driving torque corresponding to the identified reference torque value as a current value of the current for reverse driving torque.   
     
     
         16 . The method of  claim 14 , further comprising controlling the electro mechanical brake to stop providing the current for reverse driving torque to the motor, according to a speed of the motor reaching a preset target speed while the current for reverse driving torque is provided to the motor. 
     
     
         17 . The method of  claim 14 , wherein the signal for operating the anti-lock brake system is generated based on occurrence of wheel slip of the vehicle. 
     
     
         18 . The method of  claim 17 , further comprising identifying occurrence of wheel slip of the vehicle based on an output signal from a wheel speed sensor of the vehicle, while a force is applied to a brake pedal of the vehicle. 
     
     
         19 . The method of  claim 18 , comprising identifying that a force is applied to the brake pedal according to reception of an output signal from a pedal sensor configured to detect a displacement of the brake pedal. 
     
     
         20 . The method of  claim 19 , further controlling the electro mechanical brake to provide current for driving torque to the motor based on a braking force according to an output signal from the pedal sensor, while no wheel slip of the vehicle occurs.